<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <style type="text/css">
        /*定义所有div样式*/
        div
        {
            width:100px;
            height:30px;
        }
        /*定义单独div样式*/
        #div1{border:1px dashed red;}
        #div2{border:1px solid red;}
    </style>
</head>
<body>
    <div id="div1"></div>
    <div id="div2"></div>
</body>
</html>
